$ cat infile
him     mno     klm     20      76      .       +       .       klm_mango unix_00000001;
alp     fdc     klm     123   456       .       +       .       klm_mango unix_0000103;
her     tkr     klm     415     439     .       +       .       klm_mango unix_00001043;
abc     tvr     klm     20      76      .       +       .       klm_mango unix_00000001;
abc     def     klm     83      84      .       +       .       klm_mango unix_0000103;
abc     def     klm     83      84      .       +       .       klm_mango unix_1233333;
abc     def     klm     83      84      .       +       .       klm_mango unix_845454;
abc     def     klm     83      84      .       +       .       klm_mango unix_7875654;                                                                                                                                                      
abc     def     klm     83      84      .       +       .       klm_mango unix_8784552;                                                                                                                                                      
$ cat myscript.pl 
use warnings;                                                                                                                                                                                                                                
use strict;                                                                                                                                                                                                                                  
                                                                                                                                                                                                                                             
my %duplicate;                                                                                                                                                                                                                               
                                                                                                                                                                                                                                             
while ( <> ) {                                                                                                                                                                                                                               
        chomp;                                                                                                                                                                                                                               
        my @f = split;                                                                                                                                                                                                                       
        if ( ++$duplicate{ join qq[], @f[ 0..($#f-1) ] } == 1 ) {                                                                                                                                                                            
                printf qq[%s\n], $_;                                                                                                                                                                                                         
        }                                                                                                                                                                                                                                    
}                                                                                                                                                                                                                                            
$ perl myscript.pl infile                                                                                                                                                                                                           
him     mno     klm     20      76      .       +       .       klm_mango unix_00000001;                                                                                                                                                     
alp     fdc     klm     123   456       .       +       .       klm_mango unix_0000103;                                                                                                                                                      
her     tkr     klm     415     439     .       +       .       klm_mango unix_00001043;                                                                                                                                                     
abc     tvr     klm     20      76      .       +       .       klm_mango unix_00000001;                                                                                                                                                     
abc     def     klm     83      84      .       +       .       klm_mango unix_0000103;